[analyzer] When a symbol is null, we should track its constraints.

Because of this, we would previously emit NO path notes when a parameter
is constrained to null (because there are no stores). Now we show where we
made the assumption, which is much more useful.

llvm-svn: 161280
diff --git a/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp b/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp
index 27bc6fb..955e79a 100644
--- a/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp
@@ -432,8 +432,7 @@
 
     BugReport *report = new BugReport(*BT, description, N);
     report->addRange(Arg->getSourceRange());
-    report->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N, Arg,
-                                                                    report));
+    bugreporter::addTrackNullOrUndefValueVisitor(N, Arg, report);
     C.EmitReport(report);
     return;
   }